Die casting machine



June 3, 1 41. J. BRUNNER ETAL 2,243,835

DIE .IOASTING MACHINE Filed June 10, 1939 IIVVfA/TORS Ad. BRuM/ERdMAr/msss argj fflg of a die casting machine tion, the pneumatic andelectricaloperating sys- Patented June 3, 1941 UNITED STATES PATENTOFFICE 2,243,335 ma CASTINGMACHINE Anton J. Brunner, Congress Park, andBruno M, A.

Trebes,Berwyn, 111., mi trio Company, Incorpor gnors to WesternElecated, New York, N. Y., a 1 corporation of New York Application June10, 1939, Serial No. 278,386

(cleans) 5 Claims.

'. This invention relates to die casting machines,

and more particularly to die casting machines of the type in which thediecavity is evacuated prior to each casting operation.

Objects of the invention are to provide a simple,

inexpensive and eflicient die casting "machine by 7 means of whichsubstantially non-porous castings having smooth surface finishes may beproduced economically and with a minimum amount of manualefiort. 1' l Inaccordance with the above objects, one embodiment oi the inventioncontemplates the provision of a die casting machine having means forquickly evacuating the die cavity prior to each preventing the flow ofmolten metalinto the die cavity during the evacuation of the airtherefrom and means for preventing the passage of molten metal into theevacuating systemdurlngthe injection of the metal into the die cavity.

Other features and advantages of the invention will become apparent fromthe following detailed description when read in conjunction with theaccompanying drawing, in which I Fig.1 is a fragmentary verticalsectional view embodying the inventems being illustrated schematically,and v Fig. 2 is a detail sectional view taken on line 22 oi' Fis. 1. I

Referring now to the drawing, the invention is illustrated therein asembodied in a die casting machine comprising a stationary die supportingplate l0 and a movable die supporting member H to which areattachedcomplementary sta tionary and movable-die sections l3 and I4, re-

casting operation, simple and reliable means for l i seen that thepiston rod 32 extends through the cam shaft .42.

insure that the molten metal is' maintained at the proper temperature asit passes therethrough.

The charging cylinder 22 is provided near its.

upper end with an inlet port 21 which leads from the melting pot intothe interior of the cylinder.

A vertically reciprocable piston or plunger 28 is arranged to operatewithin the cylinder for forcing the molten metal into the die cavityunder the required pressure. The plunger is operatively connected to avertically reciprbcable piston 30 of an air cylinder 3| mounted abovethe charging cylinder. From its uppermost position, the piston 30 isadapted tobe moved downwardly a predetermined distance by a verticallyreciprocable rod 32 attached to a piston 33 of 'an air cylinder 34mounted above air cylinder 3|. It will be top of cylinder 3| and isadapted to engage the topof piston 30. An exhaust port 38 is provided inthe lower end of cylinder-34 below the piston 33 and the upper end ofthe cylinderis connected by a pipe 31 to a valve 38, throughwhich highpressure air from a supply line 40 may be delivered to the upper end ofthe cylinder. The valve 38 is operated by a cam 4lmounted on a camshaft42. M v

The upper end of' air cylinder 3i is connected by a pipe 43 to a doublepoppet valve 44, through which the high pressure air may be delivered tothe upper end of cylinder 3|. The valve 44 is operated by a pair of cams45 and 46 mounted on The lower end of cylinder 3| is connected by a pipeto a double poppet valve 49, through which, relatively 1 low pressureair from a supply line may bei'delivered to the lower end of thecylinder. The valve 49 is opspectively. The adjoining faces of thediesec tions'areformed to provide a die cavity I5 oi'the required shape;and the stationary die section I3 is provided with a sprue opening itleading into the die cavity. l

A suitably heated receptacle or melting pot 20 I is provided forcontaining a supply. of. molten metal to be cast, and a die chargingpump H is mountedwithin the pot. The charging Dump comprises avertically disposed charging cylinder 22 having a goose-neck nozzleportion 23 formed with a discharge passage 24 leading from the bottom ofthe cylinder. .A connecting nozzle 26 connects the disoharge passage 24with the sprue opening l5, and it will be understood that thisconnecting nozzle, as well as the exposed upper end portionof thegoose-neck nozzle, may be heated by any suitable means (none shown). to

erated by a pair of cam shaft 42. I i

For sealing the die cavity against ingressof air, an air excludingmanifold 5515 provided which comprises complementary sections 56 andearns. 5i and 52 mounted on 5| adaptedto completely: surroundthe diesections I3 and M, respectively. The manifold sections are removablyattached to the respective die sections by means of clamping screws 58,58, and rubber gaskets 59, 59 are interposed between the manifoldsections and the die sections to provide air tight seals. The adjacentfaces of the manifold sections are provided with cooperating means anair tight seal; therebetween when the die is closed. This means, in theillustrated embodiment of the invention, comprises a rubber gasket 60 inthe iaceoi manifold section 51, which is adapted to be engagedby a bead6| in l the adjacent face of manifold section 56.

When the die is closed, the manifold sections form a chamber 83surrounding the die cavity and this chamber is adapted to conmiunicatewith the die cavity through a narrow connecting passage 65 in the diesection 14. A reciprocable shutter 68 is provided for closing thepassage 85 to prevent escape of metal therethrough during castingoperations.v The shutter is operated by an air cylinder 88 throughsuitable toggle levers 68. This air cylinder is connected by flexiblepipes 1t and 12 to an air valve 13, through which the high pressure airfrom supply line 48 may be dlelivered to either end of the cylinder. Thevalve 13 is operated by a cam 14 mounted on cam shaft 42. a

The manifold chamber 83 has an outlet passage 15 connected by a pipe 18to a valve 11, through which the manifold chamber may be connected to avacuum pump 18 driven by an electric motor 18. A suitable filter 88 isprovided in the pipe line 18 for collecting any metal that may escapeaccidentally from the die cavity, thus preventing obstruction of thevacuum system.

The valve 11 is operated by a reciprocatory piston 82 mounted above thevalve in a cylinder 83 which may be integral with the valve casing. Asolenoid operated valve 85 is provided through which low pressure airfrom supply line 58 may be'delivered to cylinder 83 for operating piston82 and .thereby the valve 11-. The valve 85 is operated by a solenoid 81whose energizing winding is connected 'to electric supply lines 88through two normally open switches 88 and 88 connected in series. Switch88 is adapted to be closed upon closing of the die by a bracket 81 onthe movable die supporting member H. Switch 88 is adapted to be closedby an arm 83 on a rod 84 projecting upwardly from the piston 33 ofplunger operating cylinder 34. The switch operating arm 83 is adjustableon rod 84 to effect the closing of switch 89 only upon downward movementof plunger 28 a distance suflicient to close inlet port21. This insuresthat port 21 is closed before the solenoid operates to connect the diecavity with thevacuum system, thuspreventing the flow of molten metalinto the die cavity during the evacuation of the air therefrom.

It will be apparent to those skilled in the art that the cam shaft 42may be oscillated or rotated in any suitable manner either by powermeans under the control of a suitable timer or by manual operated means,it being essential only. that the several control valves be operated inthe proper sequence and time relation. In the illustrated embodiment ofthe invention, a hand operated lever 88 is operatively connected to camshaft 42 through suitable gearing 81 adapted to efiect approximatelyone-half revolution of the cam shaft upon movement of the hand leverfrom its neutral or starting position to its final operative position.The valve operating cams, of course, are designed to operate the valvesopen. The plunger 28 isin its uppermost position, the shutter 86 is inits open position and the valve 11 is positioned so that the die cavityis open to the atmosphere and closed to the vacuum pump. Also, valve 38is positioned so that the upper end of cylinder 84 is open to theatmosphere and valves 44 and 48 are positioned so that the upper end ofcylinder 3| is open to the atmosphere while the lower end of thiscylinder is connected to the low pressure air line 58. At this time, thevalve 13 is positioned so that it connects the upper end of cylinder 68with the high pressure air line 48 and opens the lower end of thiscylinder to the atmosphere. To operate the apparatus, the die is closedby suitable means (not shown) and the hand lever 88 is moved to theintermediate position shown in dotted outline in Fig. 1. Upon closing ofthe die, the switch 88 is closed by the switch actuating bracket 8|,thus conditioning the energizing circuit for the solenoid 81. Movementof the hand lever to the intermediate position causes rotation of camshaft 42 to a position in which cam 4| operates valve 38 to deliver highpressure air from supply line-48 to the upper end of cylinder 34,whereupon its piston 33 is moved downwardly.- The piston 38 of cylinder3| is thereby, also moved downwardly, thus moving the plunger 28 to theintermediate position indicated by the broken line 88. In moving to thisintermediate position, the plunger closes the molten metal inlet port 21of charging cylinder 22 and elevates the molten metal in the goose-neckdischarge rpassage 24 approximately up to the sprue opening 16 of thedie, as indicated by the broken memo, thus expelling air from thegoose-neck and connecting nozzles. This reduces the time required forevacuating the die cavity, since it reduces the amount of air that mustbe exhausted. It will be obvious that the movement of the hand lever tothe intermediate position also causes cams SI and 52 to operate doublepoppet valve 48 so as to open the lower end of cylinder 3| to theatmosphere. Upon movement of the plunger 28 to the intermediateposition, the switch actuating arm 83 closes the switch 98, thuscompleting the previously conditioned energizing circuit for solenoid81, whereupon the solenoid operates valve to connect the upper end ofcylinder 83 to low pressure air line 50. The piston 82 in cylinder 83 isthus moved downwardly, whereby the valve 11 is operated to connect thedie cavity It with the vacuum pump 18.

It has been found that in some instances satisfactory castings may beproduced when the air is expelled from the goose-neck and connectingnozzles by the preliminary movement of the pump plunger, evn though thedie cavity is not evacuated. but generally more satisfactory results areobtained when the die cavity is evacuated.

After a. brief interval of time sufiicient for the evacuation of the diecavity, the hand lever is moved to its final operative position and uponmovement of the hand lever to this position the valves 13 and 44areoperated. The valve 13 is operated slightly in advance of valve 44 soas to deliver high pressure air to the cylinder 68 for closing theshutter '66 prior to the injection of the molten metal into the diecavity. Following the closing of shutter 66, the valve 44 is operated todeliver high pressure air to the upper end of cylinder 3|, thus causingfurther downward movement of piston 38 and thereby the plunger28,-whereby the molten metal is forced into the evacuated die. The handlever is then returned to its original or starting position, whereuponall of the parts are returned to their original or "at rest" positionsand the casting is removed, thus completing one cycle of operation ofthe apparatus.

It will be obvious from the above description that a simple andinexpensive arrangement is provided for quickly evacuating the diecavity prior to each casting operation and that simple and reliablemeans are provided for preventing the flow of molten metal into the diecavity during the evacuation thereof and for preventing the escape ofmolten metal from the die cavity during the casting operation. It shouldbe understood, of course, that the invention is not limited to theparticular embodiments thereof herein illustrated and described, exceptinsofar as is defined by the appended claims.

What is claimed is:

1. In a die casting machine including a die having a casting cavity, adie charging means comprising a charging cylinder having an inlet portfor material to be cast and a discharging passage communicating withsaid die cavity, a reciprocable plunger in said cylinder, means forimparting an intial movement to said plunger to close said inlet portand advance the castingmaterial into said discharging passageand-thereby expel the air therefrom, means actuated by said plungermoving means upon the completion of said initial movement for evacuatingsaid die cavity, and means for thereafter imparting further movement tosaid plunger to forcibly inject the casting material into the evacuateddie cavity.

2. In a die casting machine including separable die members, oneof whichis movable for opening and closing the die, a die charging meanscomprising a receptacle for material to be cast, a charging cylinder insaid receptacle having an inlet port below the surface of said material,said cylinder having a discharging passage communieating with said die,a reciprocable plunger in said cylinder, means for imparting an initialmovement to said plungerto close said inlet port, means renderedeffective automatically by said movable die member and said plungermoving means upon movement of said movable die member to closingposition and movement of said plunger to port closing position forevacuating the die, and means for thereafter imparting further movementto said plunger to forcibly inject the casting material into the die.

3. In a die casting machine including a die having a casting cavityprovided with an air outlet passage and an inlet opening for material tobe cast, a die charging means comprising a charging cylinder in constantcommunication with said die cavity through said inlet opening, saidcharging cylinder having an inlet port for material to be cast, areciprocable plunger in said cylinder, means for imparting an initialmovement to said plungerto close said inlet port, means renderedeffective automatically by said plunger moving means upon the completionof said initial movement for evacuating the die cavity, and means forthereafter imparting further movement to said plunger to forcibly injectcasting material from said cylinder into the evacuated die cavity.

4. In a die casting machine, complementary die members cooperating toprovide a die cavity, one of said die members being movable to open andclose said cavity, a charging cylinder having a discharge passagecommunicating with said die cavity, a reciprocable plunger in saidcylinder, reciprocatory means movable in one direction for imparting arelatively slow initial move ment to said plunger to advance the castingmaterial through said discharging passage to expel the air therefrom,and die cavity evacuating means rendered eiiective automatically by saidmovable die member and said reciprocatory means upon movement of themovable die member to the closed position and movement of saidreciprocatory means a predetermined distance in said direction.

5. In a die casting'machine, complementary die members cooperating toprovide a die cavity, one of said die members being movable for openingand closing said cavity, a charging cylinder having a dischargingpassage communicating with said die cavity, a reciprocable plunger insaid cylinder, reciprocatory means movable in one direction forimparting a relatively slow initial movement to said plunger to advancethe casting material through said discharging passage to expel the airtherefrom, means for evacuating the die cavity, electromagnetic meansfor controlling said evacuating means, an electrical energizing circuitfor said electromagnetic means, two normally open control switchesconnected in series in said energizing circuit, means for closing one ofsaid switches upon movement of said movable die member to the closedposition, and means for closing the other of said switches upon movementof said reciprocatory means in said direction.

ANTON J. BRUNNER. BRUNO M. A. TREBES.

